Many conventional V-type engines, having their cylinder banks disposed at an included angle of 60.degree. normally utilize a single plane crankshaft whereby all the crankshaft throws are produced in a single plane. Such crankshafts dictate the use of an odd firing ignition angle between the cylinders, i.e., combustion between two cylinders takes place at 60.degree. with sequential pauses of 120.degree. occuring before the next two cylinders fire. Such combustion sequence is commonly referred to as an odd fire pattern which creates undesirable second order vibrations normally requiring the use of relatively large, compensating flywheels which tend to lower engine performance. Unbalance conditions prevalent in the engine are normally counteracted by the use of conventional balancers.
It is conventional practice to counteract second order vibrations to obtain substantially even firing by offsetting adjacent crankshaft pins at 30.degree.. Shaking forces are counteracted by employing suitably disposed counterbalance shafts driven by the crankshaft. Adequate crankpin bearing area is normally obtained by providing them with sufficiently large diameters. Such large crankpin diameters increase the piston connecting rod large end whereby conventional piston rods must be replaced by relatively expensive split angle piston rods which are more difficult to install and service. In addition, each adjacent pair of such crankpins include highly stressed areas at their filleted intersections. U.S. Pat. Nos. 2,632,340; 2,680,427; 3,116,724; and 3,308,680 disclose prior art engines of the type discussed above.